This application is based upon and claims the benefit of Japanese Patent Applications No. 10-199073, filed on Jul. 14, 1998, and No. 11-134809 filed on May 14, 1999, the contents of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to a semiconductor apparatus including a semiconductor element, and particular to a cooling structure for the semiconductor element such as a power MOSFET or an IGBT.
2. Description of the Related Art
A semiconductor element (semiconductor chip) such as power MOSFET or an IGBT controls large current, and accordingly produces a large amount of heat. Therefore, as a manner for cooling the semiconductor chip, various constitutions utilizing an air-cooling type radiation fin, a water-cooling type cooling block, and the like for removing heat from the semiconductor chip have been proposed by JP-A-62-92349, JP-A-63-96946, JP-A-62-141751, JP-A-61-265849, JP-A-3-20065, and the like.
However, the conventional constitutions have the following problems in a practical usage. For instance, a large size of the radiation fin is required to increase a radiation amount. When a water-cooling type cooling members is used to improve a radiation efficiency, water as refrigerant necessitates a passage thereof. The passage constitution is liable to be complicated to complicate the apparatus and to increase the size of the apparatus as a whole.
When a radiation member is attached to the semiconductor element, assembling time may be lengthened according to an arrangement of the two members. Further, because the radiation member assembled with the semiconductor element makes the semiconductor apparatus complicated and sized larger, the mountability of the semiconductor apparatus deteriorates especially when the semiconductor apparatus must be mounted in a limited space within an automotive engine room when it is used for an inverter of an electric vehicle.
When the semiconductor apparatus includes several semiconductor elements, there arise problems such that radiation members must be assembled with the respective semiconductor elements, the arrangement of the semiconductor elements may be limited according to the arrangement relationship with the radiation members, and the like. Each radiation member and each semiconductor element generally contact with each other through an insulation substrate for holding the semiconductor element, and a radiation passage for transmitting heat from the semiconductor element to the radiation member is provided to improved the radiation property. In this case, radiation grease is disposed between both members to fill gaps produced by surface irregularity and waviness to enhance adhesiveness therebetween. However, because the radiation grease includes oil as a main component, the viscosity of the grease is lowered by heat produced from the element (for instance, at 150xc2x0 C. or more). The grease with the lowered viscosity is liable to flow out to deteriorate the adhesiveness described above, resulting in deterioration of the radiation property.
The present invention has been made in view of the above problems. A first object of the present invention is to provide a practical novel structure for radiating heat produced from a semiconductor element in a semiconductor apparatus. A second object of the present invention is to provide a semiconductor apparatus having a radiation structure that can be easily assembled. A third object is to simplify the radiation structure. Also, a fourth object is to improve mountability of the semiconductor apparatus, and a fifth object is to improve adhesiveness between an insulation substrate holding a semiconductor element and a radiation member.
Briefly, according to a first aspect of the present invention, a semiconductor apparatus has a substrate unit composed of a semiconductor element and a pair of insulation substrates holding the semiconductor element therebetween, and first and second radiation members for radiating heat produced from the substrate unit and defining a recess therebetween into which the substrate unit is inserted in an insertion direction. The semiconductor apparatus further has a fixing member for fixing the substrate unit within the recess by being inerted into one of the first and second radiation members in the insertion direction.
Thus, because the semiconductor unit and the fixing member can be inserted relative to the radiation members in the same direction, the assembling becomes easy. Because the substrate unit is sandwiched between the first and second radiation members, the heat produced from the substrate unit can be radiated from both side thereof, resulting in high radiation property.
According to a second aspect of the present invention, a semiconductor apparatus includes first and second substrate units, first and second pairs of radiation members defining first and second recesses therebetween which respectively hold the first and second substrate units therein, and a common pushing member disposed between the first and second pairs of radiation members for pushing the first and second pairs of radiation members to fix the first and second substrate units in the first and second recesses. This makes assembling easy as well.
According to a third aspect of the present invention, a semiconductor apparatus includes a plurality of substrate units, and a radiation member holding the plurality of substrate units for radiating heat from the substrate units and having a single refrigerant passage therein in which refrigerant flows for absorbing the heat. In this case, the single refrigerant passage does not require any connection members, resulting in simple structure of the water-cooling type semiconductor apparatus.
According to a fourth aspect of the present invention, a semiconductor apparatus includes a substrata unit, and a radiation member having a first wall on which the substrate unit is disposed and a second wall on an opposite side of the first wall. The second wall is flat. The flat second wall makes mountability of the semiconductor apparatus easy.
According to a fifth aspect of the present invention, a semiconductor apparatus includes a substrate unit, a radiation member disposed in contact with the substrate unit through a contact material for radiating heat produced from the substrate unit. The contact material is composed of a resin material having thermal resistance and flexibility and a thermal-conductive compounding material contained in the resin material. In this case, the contact material fills gaps produced in the interface between the substrate unit and the radiation member by surface irregularity and waviness of the substrate unit and the radiation member, realizing high adhesiveness at the interface. Further, even when the radiation member and the substrate unit are relatively displaced, the contact material can follow the displacement to keep the high adhesiveness. This results in improvement of the radiation property.